Synthesis and applications of porous spg (shirasu porous glass) microspheres

Omi, Shinzo; Katami, Ken'ichi; Taguchi, Tetsuya; Kaneko, Kazuyoshi; Iso, Mamoru

doi:10.1002/masy.19950920124

Cited by 30 publications

(20 citation statements)

References 1 publication

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“…Average diameters of polymer particles, referred to as dp in the later tables, were mainly determined from SEM photographs. Experimentally observed ratios of the swelling can be expressed as ( dp/del) , 3 and compared with the theoretical ratio, S,, defined in eq. ( 1 ) .…”

Section: Analysesmentioning

confidence: 99%

Synthesis of uniform PMMA microspheres employing modified SPG (shirasu porous glass) emulsification technique

Omi

Katami

Taguchi

et al. 1995

J of Applied Polymer Sci

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SYNOPSISApplication of the particulate microporous glass membrane (SPG) was extended to the synthesis of fairly monodisperse poly(methy1 methacrylate) (PMMA) microspheres. Hydrophilic monomers have been believed to yield polymer particles of a broad size distribution when the SPG technique was employed. This difficulty was overcome by adopting the droplet swelling technique. The primary uniform emulsion composed of a mixture of hydrophobic diluent (and/or monomer), cosurfactant, and initiator was prepared with an SPG membrane and was allowed to absorb MMA (and diluent) under the principle of the degradative diffusion process from droplets in the secondary emulsion. The coefficient of variation of PMMA spheres was around 10%. Porous PMMA spheres possessing up to 185 m2/g of specific surface area were obtained as well as one-eyed spheres and smooth and solid spheres. 0

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Section: Analysesmentioning

confidence: 99%

Synthesis of uniform PMMA microspheres employing modified SPG (shirasu porous glass) emulsification technique

Omi

Katami

Taguchi

et al. 1995

J of Applied Polymer Sci

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“…Shirasu porous glass (SPG) membranes with cylindrical, interconnected, uniform microspores, which are synthesized from CaO-Al 2 O 3 -B 2 O 3 -SiO 2 type glass, are the most suitable membrane presently available for a membrane emulsification medium [8]. Generally, the membrane must be capable of being wetted by the continuous phase, but not by the dispersed phase in membrane emulsification, which means that hydrophilic membranes are available for preparing oil-in-water (O/W) emulsions and hydrophobic ones for water-in-oil (W/O) emulsions [9].…”

Section: Introductionmentioning

confidence: 99%

Preparation of water-in-oil emulsions using a hydrophobic polymer membrane with 3D bicontinuous skeleton structure

Zhou

et al. 2015

Journal of Membrane Science

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“…[17][18][19][20] The uniformity in size of the droplets obtained by the emulsification process was retained during the later preparation stages. While doing these experiments, we have observed various kinds of particle morphologies, one-eyed, blood cell (collapsed sphere), and hollow particles.…”

Section: Introductionmentioning

confidence: 99%

Morphology development of 10-?m scale polymer particles prepared by SPG emulsification and suspension polymerization

Omi

Senba

Nagai

et al. 2001

J. Appl. Polym. Sci.

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Classicalparticle morphologies, core‐shell, hemisphere, sandwich, and so on, were all reproducible by starting from ca. 10‐μm uniform droplets composed of monomers, initiator, solvents, and polymer, and polymerizing them by subsequent suspension polymerization. SPG (Shirasu porous glass) membrane was employed to form uniform size droplets having the coefficient of variation (CV) around 10%. Styrene (ST) and acrylic monomers were used as monomers, and their polymers were dissolved in the droplets to investigate the development of phase separation. When hydrophilic methyl methacrylate (MMA) was polymerized in the droplets with a mixed solvent consisting of hydrophilic hexanol (HA) and hydrophobic benzene and hexadecane (HD), the resulting morphology shifted from hemisphere to sandwich and eventually to PMMA/solvent core‐shell with increasing hydrophilicity of the mixed solvent. The sandwich was converted to the core‐shell after several weeks elapsed. As styrene was added to MMA, the morphology shifted from hemisphere core/solvent shell to raspberry core/solvent shell as the fraction of ST increased. The domain of the mixed solvent in the raspberry core was reduced with increasing the hydrophilicity of the mixed solvent. All these morphologies were eventually converted to the copolymer core/solvent shell. When a mixed monomer of styrene and MMA dissolving polystyrene (PS) was polymerized, the resulting morphology shifted from salami to core‐shell with increasing the MMA fraction in the comonomer. The salami particles were then swollen with toluene, and after the swelling, toluene was removed under the different temperature and pressure. The final particle morphology converted to the core‐shell with a milder rate of toluene removal which was predicted from the thermodynamic model. When styrene and cyclohexyl acrylate (CHA), a pair with widely different reactivity ratios, were copolymerized, salami morphologies, with tiny CHA‐rich domains dispersed in the matrix, were obtained even at a higher fraction of CHA in comonomer. Effects of glass transition temperature of the polymers, molecular weight, and the composition of copolymers were taken in consideration whenever the final morphologies were discussed. By these experiments, the authors tried to demonstrate an advantage of using large uniform spheres for the particle morphology studies. SPG emulsification technique was a potential tool because of its free formulation of the droplets, and the subsequent polymerization could undergo without the breakup or coalescence of the droplets. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2200–2220, 2001

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Synthesis and applications of porous spg (shirasu porous glass) microspheres

Cited by 30 publications

References 1 publication

Synthesis of uniform PMMA microspheres employing modified SPG (shirasu porous glass) emulsification technique

Synthesis of uniform PMMA microspheres employing modified SPG (shirasu porous glass) emulsification technique

Preparation of water-in-oil emulsions using a hydrophobic polymer membrane with 3D bicontinuous skeleton structure

Morphology development of 10-?m scale polymer particles prepared by SPG emulsification and suspension polymerization

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